This application claims priority from U.S. Provisional Application Ser. No. 61/491,559 filed May 31, 2011.
The present invention relates to a device for injecting gas into tubes in a chemical reactor, and more specifically for injecting gas into the bottom of the tubes. The gas may be injected for the purpose of pressure testing the tubes, for blowing out the tubes in order to clean them, or for other purposes.
Many chemical reactors are essentially a large shell and tube heat exchanger vessel, with the reaction occurring inside the tubes and a coolant circulating in the vessel outside the tubes. A chemical reactor vessel also can be a simple tank with a single volume of catalyst inside it, or it may be a single large tube. Some chemical reactions occur in furnace or reformer tubes, which may be a part of a system with 10 to 500 or more such tubes. In any of these reactor vessels, catalyst, typically in the form of pellets (and other types of pellets that are not catalyst), may be loaded into the reactor to facilitate the reaction. The pellets are replaced periodically.
It may be advantageous to inject gas into the tubes in order to do back-pressure testing of the catalyst-loaded tubes in the reactor to ascertain the adequacy of the loading procedure. It also may be advantageous to inject gas into the tubes in order to clean the tubes. In the prior art, the injection of gas typically is done from the top. It is difficult or impossible to use existing equipment to inject gas from the bottom, especially if there is more than one injector and gas is being injected into more than one reactor tube at a time.